During the coming year, a number of experiments will be conducted to confirm the recent findings regarding pheromonal and stress-induced ovulation. Experiments will be conducted to isolate genetically the neuroendocrine mechanisms involved in the stress--ovulatory response of the immature female induced by exposure to a mature female mouse, and to compare it to the mechanisms involved in the male pheromonally-induced ovulation. Analysis will be continued into the hypothalamic levels of the biogenic amines, norepinephrine, dopamine, serotonin, and acetylcholine, as well as the respective synthetic and inactivating enzymes before, during, and after exposure to various exteroceptive stimuli (male or female pheromones, sound, shock, change in environment, or light) in appropriately primed female mice in order to establish the neurobiochemical events involved in this psychobehavioral phenomenon. Generally, biochemical studies will involve direct fluorimetric analyses of the biogenic amines accompanied by determinations of turnover rate, dynamics and equilibrium constants under the various experimental conditions employed to induce pheromonal, light, sound, and shock ovulation. Additionally, differential pharmacologic inhibitors of the various amines will be used to alter the levels of these amines, and observe the resultant effects upon facilitation or inhibition of ovulation in the appropriate primed immature females. If time permits, electrophysiological determinants as correlates of the various stressors will be gathered in an effort to relate exteroceptive stimuli to neuroendocrine mechanisms which are accompanied by major electrophysiological changes, especially in the hypothalamus and hippocampus.